Continuous metal castings

ABSTRACT

The continuous casting of metal blanks is effected by using a false blank to initiate the casting process, the blank being cast through a mould on to the upper end of the false blank. The false blank is formed of at least two sections screw-threaded together. These sections are of a length to conform with the length of the sections into which the cast blank will be cut.

United States Patent [191 Fl w Peytavin Oct. 29, 1974 [54] CONTINUOUSMETAL CASTINGS 3,239,894 3/1966 Masters [64/274 [75] I In entor: PierrePeytav n Neumy upse ne, 3,565,157 2/l97l Peytavln 164/282 X France 73Assignee: Societe Civile DEtudes De Primary Examiner-Andrew R. JuhaslCertifugation, Paris, France Assistant Examiner.lohn S. Brown Filed: g1972 Attorney, Agent, or FirmBrisebois & Kruger [2]] Appl. No.: 282,121

[57] ABSTRACT [30] Foreign Application Priority Data Aug. 25, l97lFrance 71.30834 The ontinuous casting of metal blanks is effected byusing a false blank to initiate the casting process, the [52] U.S. Cl.164/82, 164/282 blank being cast through a mould on to the upper end[51] Int. Cl 322d 11/00 of the false blank, The false blank is formed ofat least Fleld 0f Search two sections screw-threaded together. Thesesections v 85 are of a length to conform with the length of the sectionsinto which the cast blank will be cut.

, [56] References Cited UNITED STATES PATENTS 5 Claims, 6 DrawingFigures 2,l7 6,990 lO/l939 Crampton 164/274 Pmmmnm 29 1914 smnurz .Qgya

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CONTINUOUS METAL CASTINGS The invention relates to a process andapparatus for initiating a continuous casting process for metals, suchas steel, in order to obtain solid or hollow metallic bars or blanks(hereinafter for convenience simply called blanks).

It is at present known to make, by a continuous casting process,metallic blanks, for example of steel, by introducing molten metal intoa cooled mould, the shape of which corresponds to that of the blankwhich it is desired to make, and by extracting the solid blank at thebottom of the mould.

Metallic blanks continuously produced in this way are then cut intosuitable lengths.

This cutting is effected at the lower part of the continuous castingapparatus each blank length being received in a tipping device whichturns them from a vertical to a horizontal altitude and discharges theminto a removal device or conveyor.

In conventional continuous casting processes the blank, duringproduction, is not rotated about its longitudinal axis but is merelyurged downwards by an extraction device. ln this case, the blank mayalso be cut into lengths as indicated above.

The processes and apparatus used presently are satisfactory where blanksof relatively small cross-section are being produced. However, theseprocesses and apparatus have serious drawbacks when it is desired toproduce bars of substantial cross-section in large capacity apparatus.

In fact, considering the various factors which determine cooling of themetal, there exists in the blank during production a core of moltenmetal extending from the upper part of the apparatus where the mould,which serves to define the cross section of the blank, is located to themiddle region of the blank up to distances which may amount to metres ortens of metres, when bars of substantial cross-section are beingproduced in large capacity apparatus.

Naturally, the blanks produced cannot be cut in the zone where themolten metal is located at the centre of the blank, and equally, forsafety reasons, sectioning of the blank can only be effected beyond thepoint where the blank has become solidified.

This height of molten metal core is critical as regards the dimensionsof the casting apparatus for a given section and rate of throughputsince it is necessary to provide for such a height, a satisfactory guideand driving means for the bar in the course of solidification.

Moreover, it is also known to use, for initiating a continuous castingprocess as refered to above, a false blank which is introduced into theapparatus before the casting begins so as to occupy the place of theblank in the course of solidifying, while the apparatus is operating,and to retain the molten metal at the beginning of the casting.

The molten metal which is then introduced into the mould is fused to theupper part of the false blank which is also guided and moved bythedevice provided for the continuous operation, so that there is thusobtained, as soon as the continuous casting process has got under way, afunctioning which is practically the tion, a false blank must beprovided the length of which corresponds to the height of the apparatuswhich is (as has previously been explained) determined by the height ofthe blank in which there is a certain amount of molten metal at thecentre.

Naturally the first cut which may be made during the continuous castingprocess may only be made above the false blank.

In consequence, the tipping device which is located below the knownapparatus must have a sufficient length to receive and tilt the falseblank.

This constitutes a serious drawback when a blank of large cross-sectionis formed in large capacity apparatus, since, in this case, thesolidification height is very great, which necessitates a very longfalse blank. Now, as it happens, in this case it is not necessary tomake metal sections of great length, precisely due to the largecross-section of these pieces.

Consequently, in the present state of the art, the tipping device, whichis located at the lower part of the apparatus, must be dimensioned topivot the false blank and this is found to be much bigger than would benecessary for pivoting the blank sections, since these sections areusually notably shorter than the false blank used for starting theprocess.

An object of the present invention is therefore a process and apparatuswhich make it possible to obviate or mitigate this drawback very simply.

According to the present invention a process for initiating a continuouscasting process for metals, such as steel, by using a false blankintended to serve as the lower part of the blank during production, saidflase blank and the blank sections produced being received anddischarged by a device located at the lower part of the castingapparatus, and the false blank being obtained by interconnecting aplurality of sections each having a length corresponding to the lengthof the blank sections which it is desired to cast, the false blanksections being screwed together, and each false blank section whichreaches the bottom the guide and extraction means of the apparatus beingseparated from its upper section by a relative rotary movement whicheffects the unscrewing and separation of the lower section which is thenreceived in' the discharging device.

In a preferred embodiment of the invention, the process is applied to acontinuous rotary casting process in which the blank being formed isrotated about a vertical axis.

In this case, the lower section of the false blank is unscrewed verysimply by means of a gripper or locking device located at the lower partof the guiding and extracting means, for example substantially on alevel with the device for cutting the blank into sections, the directionof the screw-threading allowing the unscrewing of the lower section whenthis section is held stationary while the upper sections continue torotate.

In the case where the process according to the'invention is applied to acontinuous static casting process the unscrewing of the lower falseblank section may easily be effected by rotating the lower section ofthe false blank about its vertical axis. This rotation may be effectedby any device which grips the lower part of the false blank and rotatesit.

It will be seen that the process according to the invention makes, itpossible to subdivide the false blank very easily into as many sectionsas are desired, each section of the false blank being detached, tippedand removed by means of the tipping device which is dimensioned .solelyas a function of the cast metallic blank sections which it must handleduring the continous casting process proper.

Moreover, the use of a sectioned false blank has the advantage offacilitating the introduction of the false blank into the apparatus bythe tipping device at the instant when one prepares to initiate thecontinuous casting. if so desired, the false blank sections may also beintroduced successively, since they are of reduced dimensions, at theupper part of the apparatus, i.e., through the casting mould, thesections being moved down progressively while the subsequent sectionsare introduced successively at the top.

The present invention is also apparatus for continuously castingmetallic blanks, for example of steel, in which molten metal isintroduced into a cooled mould, and the blank during solidificationbeing held in guide and extraction means disposed vertically beneath themould, the apparatus being characterised by the fact that a device, forreceiving and discharging the blank sections, disposed at the lower partof the apparatus, is dimensioned as a function of the length of theblank sections which it is desired to case, and that a false blanklocated in the guide and extraction means at the beginning of thecontinuous casting process, is subdivided into sections, the length ofeach which is at the' most substantially equally to the length of theblank sections which it is desired to cast, the various flase blanksections being screwed together, means being located, preferably betweenthe lower part of the guiding and extracting means and the dischargedevice, which is capable of imparting to the lower false blank section arelative movement with respect to the other upper false blank sections,so as to unscrew said lower section, which may then be discharged by thedischarge device, or by reversing the direction of rotation, to assemblethe secions of the false blank before the casting begins.

In a modification of the apparatus according to the invention, which isapplied to continuous rotary casting processes, the means for impartingthe relative movement to the lower section of the false blank isconstituted by a holding device or similar means which prevents thelower section from rotating.

In the embodiment in which the invention is applied to a continuousnon-rotary casting process, the means which impart the relative movementto the lower section is constituted by a gripping device, which engagesthe lower section and rotates it about a vertical axis.

Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying drawings, in which:

FIGS. 1, 2 and 3 are diagrammatic elevation views showing three stagesof the process for removing the false blank sections, in the case of acontinuous rotary casting process; and,

FIGS. 4, 5 and 6 are diagrammatic views showing three stages of theremoval of the lower sections of the false blank in the case of acontinuous non-rotary casting process.

There is diagrammatically shown in FIGS. 1, 2 and 3 a continuous rotarycasting apparatus according to the invention.

The apparatus comprises at its upper part a cooled mould l rotatingabout its vertical axis, into which is directed a jet 2 of molten metalwhich serves to produce the blank.

Below the mould 1, guide rollers 3, which are diagrammatically shown,are located, the function of which is to hold the blank as it solidifieslaterally, while it is moved down by extractor rollers 4 which are alsoarranged in a casing rotating about a vertical axis, in the direction ofthe arrows F of FIG. I.

In order to initiate the continuous casting process, a false blank 5constituted by an assembly of two sections 5a and 5b interconnected byscrew threading 6, is disposed between the rollers 3 and 4.

At the bottom of the apparatus a tipping device is diagrammaticallyshown, which device receives the blank sections and discharges themafter having pivoted them about a horizontal axis 8.

At 9 there is shown, in a purely diagrammatic manner, a device forcutting the blank into convenient lengths. This device 9 may be of anyconvenient from. It may be constituted by a saw or a cutting flame, forexample.

In addition to the cutting device 9, there is diagrammatically shown agripper device 10.

This device 10 which may be of any convenient form is constituted inthis instance, by two jaws, for example, disposed on either side of theaxis of the blank being cast, said jaws allowing, in the open position,free passage of the false blank while in the closed position they engagethe false blank and prevent it from rotating.

According to the invention, the sense of the screwthreading 6 and thedirection of rotation of the blank as indicated by the arrow F isselected so that when the lower section of the false blank is heldstationary an unscrewing of this section occurs with respect to thesection immediately above it.

In the device which. has just been described and which is shown in FIGS.1 to 3, the false blank is constituted by two sections. Naturally, thefalse blank may have any convenient number of sections dependent on eachsection corresponding in length to the length of each blank sectionbeing cast and the dimensions of the tipping device 7.

The total length of the false blank corresponds to the total height ofthe apparatus i.e., to the length of the apparatus between the mould land the extraction or guide rollers 3, 4.

The process for initiating the continuous casting will now be described.

FIG. 1 shows the two false blank sections positioned between the guideand extraction rollers 3, 4 at the instant when casting begins.

The false blank is rotated in the direction of arrows F in the samemanner as the blank being cast is rotated during the casting operation.

The molten metal firstly enters the mould at 2, where it becomes solidand adheres to the upper part of the upper section 5b of the falseblank. Atlthe same time, the extractor rollers 4 slowly move theassembly constituted by the false blank and solidifying metal which iscommencing to form a blank downwards.

This process continuing, the position shown in FIG. 2 is reached, inwhich the lower section 5a of the false blank lies entirely below theextractor rollers 4, while being received in the tipping device 7,whilst a corresponding length of the cast blank 11 is formed above thesection 5b of the blank.

According to the invention, the section 5a of the false blank is grippedby the device which prevents the section 5a from rotating, while thesection 5b continues to rotate at the same time as the bar 11 which isbeing cast.

There occurs very quickly an unscrewing of the section 50 of the falseblank, which is thus released from the section 5b.

The gripper device 10 is then loosened, as shown in FIG. 3, and thesection 5a falls into the tipping device 7 which, by pivoting about theaxis 8 in the direction of the arrow F, dispose the section 5a in thehorizontal position and discharges it so that the sequence can berepeated.

The gripper device 10, which prevents the lower section 5a fromrotating, may preferably be moved slightly downwards so as to follow thedownward movement of the section 5a, a movement which is necessary, onthe one hand, for the vertical extraction speed of the blank and, on theother hand, for the axial component of the unscrewing movement of thesection 5a with respect to the section 5b.

The process is continued until the section 5b of the false blank hasarrived substantially in the position occupied by the section 5a in FIG.1.

In this case, the section 5b is released by using the cutting device 9for cutting the blank 11 into lengths just above the section 5b, whichis then extracted by the tipping device 7.

Of course, if the false blank was constituted by a greater number ofsections, there would be located between the section 5a and the section512 shown in FIGS. 1 to 3, intermediate sections which would be releasedin same manner as the section 5a, from the upper sections by means ofthe locking device 10.

FIGS. 4 to 6 show the application of the invention in the case of anon-rotary continuous casting process.

FIGS. 4 to 6 show substantially the same components as FIGS. 1 to 3,with, however, the following differences.

The extraction and guide device comprises only rollers 4, only certainof which may be propulsive.

In fact, it is unnecessary to provide rollers having a vertical axis 3since the blank does not rotate.

The main difference relates to the device 10, which effects unscrewingof the lower section 5a of the false blank.

In the embodiment of FIGS. 4 to 6, this device 10 is formed not only toengage the section 5a but also to rotate it in a direction such that thesection 5a is unscrewed with respect to the section 5b.

The operation, in the case of the embodiment in FIGS. 4 to 6, is exactlythe same as that which has been described with reference to FIGS. 1 to3, with the exception that the part of the false blank, which is locatedbetween the cutting device 9 and the mould 2, is not subjected to anyrotation about a vertical axis, but only to a downward extractionmovement, while the lower section of the false blank is rotated insteadof being blocked to ensure its unscrewing so that it can be introducedinto the tipping device 7.

It is seen that the invention makes it possible to extract the falseblank easily, by means of tipping devices of small dimensions, in thecase of both continuous rotary casting operations and continuousnon-rotary casting operations.

Naturally, the embodiments which have been described above are notlimitative and any desirable modification may be made thereto withoutdeparting from the scope of the present invention.

In particular, it will be manifest that the invention is applicable bothto the production of solid as well as hollow blanks, and that thecross-sectional shape of the blanks has no influence in the carrying outof the process.

Moreover, naturally one would not depart from the scope of the inventionby removing the false blank sections, or blank sections by means of adevice other than the tipping device which has been described.

In particular, for this purpose, a device could be used which receivesthe false blank sections. or cast blank sections vertically and movesthem parallel to each other in order to extract them vertically afterhaving disengaged them from the continuous casting line.

What is claimed is:

1. In a method of initiating the continuous casting of a metallic objectwhich is to be cut into sections, which method comprises the steps ofintroducing a false blank beneath the metal being cast to form saidobject, and receiving said false blank and object successively in guidemeans and a tipping extractor beneath said guide means, which extractoris dimensioned to tip severed sections of said object having at most apredetermined maximum length out of alignment with said guide means,

the improvement which comprises the steps of employing a false blankcomprising a plurality of sections which are screwed together, thelength of each section being at most equal to said maximum length, andseparating the lowermost section of said false blank from the remainderof said false blank during the descent of said false blank by unscrewingsaid lowermost section therefrom, and then tipping said lowermostsection in said tipping extractor once it has passed below said guidemeans.

2. A process according to claim 1, in which the blank being cast isrotated about a vertical axis.

3. In a process for initiating the continuous rotary casting about avertical axis of a metallic object which is to be cut into sections,which method comprises the steps of introducing a false blank beneaththe metal being cast to form said object, and receiving said false blankand object successively in guide means'and a tipping extractor beneathsaid guide means, which extractor is dimensioned to tip severed sectionsof said object having at most a predetermined maximum length out ofalignment with said guide means,

the improvement which comprises the steps of employing a false blankwhich rotates with said object and comprises a plurality of sectionswhich are screwed together, the length of each section being at mostequal to said maximum length and separating the lowermost section ofsaid false blank from the remainder of said false blank by unscrewingsaid lowermost section therefrom by preventing rotation of saidlowermost section and tipping said lowermost section in said tippingextractor once it has passed below said gudie means.

4. A process according to claim 1, in which the blank being cast is notrotated, the lower section of the false blank is rotated to unscrew saidsection.

5. A process as claimed in claim 1 comprising the step of employing afalse blank having sections substantially equal in length to the severedsections of said object.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,8,333Dated October 29 197 Inventor s) P IERRE PEY'IAVIN It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

[73] Assignee: Societe Civile D'Et'udes De Centrifugation,

Paris France Signed and sealed this th day of April 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. IMSGE-I Commissioner of Patents Attesting;Officer and Trademarks FORM PO-IOSO (10-69) USCOMM-DC 60376-P69 l 0.5.GOVERNMENT PRINTING OFFICE 2 ll, O-Ji-SM.

1. In a method of initiating the continuous casting of a metallic objectwhich is to be cut into sections, which method comprises the steps ofintroducing a false blank beneath the metal being cast to form saidobject, and receiving said false blank and object successively in guidemeans and a tipping extractor beneath said guide means, which extractoris dimensioned to tip severed sections of said object having at most apredetermined maximum length out of alignment with said guide means, theimprovement which comprises the steps of employing a false blankcomprising a plurality of sections which are screwed together, thelength of each section being at most equal to said maximum length, andseparating the lowermost section of said false blank from the remainderof said false blank during the descent of said false blank by unscrewingsaid lowermost section therefrom, and then tipping said lowermostsection in said tipping extractor once it has passed below said guidemeans.
 2. A process according to claim 1, in which the blank being castis rotated about a vertical axis.
 3. In a process for initiating thecontinuous rotary casting about a vertical axis of a metallic objectwhich is to be cut into sections, which method comprises the steps ofintroducing a false blank beneath the metal being cast to form saidobject, and receiving said false blank and object successively in guidemeans and a tipping extractor beneath said guide means, which extractoris diMensioned to tip severed sections of said object having at most apredetermined maximum length out of alignment with said guide means, theimprovement which comprises the steps of employing a false blank whichrotates with said object and comprises a plurality of sections which arescrewed together, the length of each section being at most equal to saidmaximum length and separating the lowermost section of said false blankfrom the remainder of said false blank by unscrewing said lowermostsection therefrom by preventing rotation of said lowermost section andtipping said lowermost section in said tipping extractor once it haspassed below said gudie means.
 4. A process according to claim 1, inwhich the blank being cast is not rotated, the lower section of thefalse blank is rotated to unscrew said section.
 5. A process as claimedin claim 1 comprising the step of employing a false blank havingsections substantially equal in length to the severed sections of saidobject.